A Two‐year Circulatory Follow‐up of Physical Training After Myocardial Infarction

Circulatory effects of physical training after myocardial infarction have been evaluated in six middleaged men. The schedule consisted of studies before training, after a two month's programmed training, and after an additional two years' spontaneous physical activity. After two months three patients stopped the excess activity while three continued it at different levels. Exercise tolerance, measured by ergometry, increased in all subjects after two months. The symptoms occurred at identical heart rates but external work loads evoking these heart rates were higher. After additional two‐year activity both the loads and heart rates tolerated were higher. In the subgroup who stopped the activity, exercise tolerance was largely at the pretraining level. A decrease in tension‐time index and no change in heart volume explained the change at two months. The same parameters could be invoked to explain the deterioration of the inactive group after two years. After continued excess activity tension‐time indices during exercise were higher in two patients than the level at which symptoms occurred before training. Changes in heart volume were small after two years. It is concluded that short‐term and long‐term training responses differ in the mode by which they increase exercise tolerance. After two months' training hemodynamic changes decreasing oxygen demand of the heart are sufficient to explain the progress, whereas after two years' activity additional, so far unverified, factors are involved.